This invention relates to new 3-substituted 2-propenimidamide derivatives, which may also be referred to as 3-substituted-propenamidines, the method of manufacturing the same, therapeutic compositions containing these compounds and therapeutic uses thereof. More specifically the invention concerns N'-cyano and N'-carbamoyl derivatives of 3-furyl-, 3-thienyl- and 3-phenylpropenimidamides, pharmaceutical compositions containing these compounds and a method of treating peptic ulcers therewith.